Method and apparatus for decoupling uplink latency using common uplink burst in tdd subframe structure

ABSTRACT

Wireless communications systems and methods related to decoupling uplink latency using common uplink (UL) burst in Time Division Duplex (TDD) sub-frame structure are disclosed. User equipment (UE) can transmit to a base station a common UL burst in each sub-frame communicated between UE and the base station, wherein the common UL burst comprises at least one of: a physical layer (PHY) acknowledgement (ACK), a scheduling request (SR), a buffer status report (BSR), or a sounding reference signal (SRS). UE can be further configured to transmit scheduled UL payload data in at least one common UL burst of at least one sub-frame communicated between the UE and the base station.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/163,261, filed Oct. 17, 2018, which is acontinuation of U.S. Non-Provisional patent application Ser. No.15/211,604, filed Jul. 15, 2016, now U.S. Pat. No. 10,123,347 whichclaims priority to and the benefit of the U.S. Provisional PatentApplication No. 62/263,466, filed Dec. 4, 2015, the disclosure of eachof which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

This application relates to wireless communication systems, and moreparticularly to decoupling uplink latency using common uplink bursts inTime Division Duplex (TDD) sub-frame structures.

INTRODUCTION

Growing demand for data and throughput has been envisioned for 5thGeneration (5G) networks, which requires a broader frequency spectrum. Aplethora of unpaired spectrum is available at a high frequency band,which is also less expensive than the paired spectrum at frequencies of2 GHz and below. Wireless communications on the unpaired spectrum istypically performed in Time Division Duplex (TDD) mode, where uplinktransmission (e.g., transmission from user equipment (UE) to evolvedNode B (eNB)) and downlink transmission (e.g., transmission from eNB toUE) share the same frequency spectrum, but are separated in time.

BRIEF SUMMARY OF SOME EMBODIMENTS/EXAMPLES

The following summarizes some aspects of the present disclosure toprovide a basic understanding of the discussed technology. This summaryis not an extensive overview of all contemplated features of thedisclosure, and is intended neither to identify key or critical elementsof all aspects of the disclosure nor to delineate the scope of any orall aspects of the disclosure. Its sole purpose is to present someconcepts of one or more aspects of the disclosure in summary form as aprelude to the more detailed description that is presented later.

For example, in an aspect of the disclosure, a method for wirelesscommunications includes transmitting, from a user equipment (UE) to abase station (BS), a common uplink (UL) burst in each sub-framecommunicated between the UE and the BS, wherein the common UL burstcomprises at least one of a physical layer (PHY) acknowledgement (ACK),a scheduling request, a buffer status report (BSR), or a soundingreference signal (SRS), and transmitting, from the UE, scheduled ULpayload data in at least one common UL burst of at least one sub-framecommunicated between the UE and the BS.

In an additional aspect of the disclosure, an apparatus includes atransmitter configured to transmit, to another apparatus, a commonuplink (UL) burst in each sub-frame communicated between the apparatusand the other apparatus, wherein the common UL burst comprises at leastone of a physical layer (PHY) acknowledgement (ACK), a schedulingrequest (SR), a buffer status report (BSR), or a sounding referencesignal (SRS), and a transmitter is further configured to transmitscheduled UL payload data in at least one common UL burst of at leastone sub-frame communicated between the apparatus and the otherapparatus.

In an additional aspect of the disclosure, an apparatus includes meansfor transmitting, to another apparatus, a common uplink (UL) burst ineach sub-frame communicated between the apparatus and the otherapparatus, wherein the common UL burst comprises at least one of aphysical layer (PHY) acknowledgement (ACK), a scheduling request (SR), abuffer status report (BSR), or a sounding reference signal (SRS), andwherein the means for transmitting is further configured to transmitscheduled UL payload data in at least one common UL burst of at leastone sub-frame communicated between the apparatus and the otherapparatus.

In an additional aspect of the disclosure, a computer-readable mediumhaving program code recorded thereon includes program code comprisingcode for causing a user equipment (UE) to transmit, to a base station(BS), a common uplink (UL) burst in each sub-frame communicated betweenthe UE and the BS, wherein the common UL burst comprises at least one ofa physical layer (PHY) acknowledgement (ACK), a scheduling request (SR),a buffer status report (BSR), or a sounding reference signal (SRS), andcode for causing the UE to transmit scheduled UL payload data in atleast one common UL burst of at least one sub-frame communicated betweenthe UE and the BS.

In an additional aspect of the disclosure, a method for wirelesscommunications includes receiving, at a base station (BS) from a userequipment (UE), a common uplink (UL) burst in each sub-framecommunicated between the UE and the BS, wherein the common UL burstcomprises at least one of a physical layer (PHY) acknowledgement (ACK),a scheduling request (SR), a buffer status report (BSR), or a soundingreference signal (SRS), and receiving, at the BS, an UL payload datawithin at least one common UL burst of at least one sub-framecommunicated between the UE and the BS.

In an additional aspect of the disclosure, an apparatus includes areceiver configured to receive, from another apparatus, a common uplink(UL) burst in each sub-frame communicated between the other apparatusand the apparatus, wherein the common UL burst comprises at least one ofa physical layer (PHY) acknowledgement (ACK), a scheduling request (SR),a buffer status report (BSR), or a sounding reference signal (SRS), andwherein the receiver is further configured to receive an UL payload datawithin at least one common UL burst of at least one sub-framecommunicated between the other apparatus and the apparatus.

In an additional aspect of the disclosure, an apparatus includes meansfor receiving, from another apparatus, a common uplink (UL) burst ineach sub-frame communicated between the other apparatus and theapparatus, wherein the common UL burst comprises at least one of aphysical layer (PHY) acknowledgement (ACK), a scheduling request (SR), abuffer status report (BSR), or a sounding reference signal (SRS), andwherein the means for receiving is further configured to receive an ULpayload data within at least one common UL burst of at least onesub-frame communicated between the other apparatus and the apparatus

In an additional aspect of the disclosure, a computer-readable mediumhaving program code recorded thereon includes program code comprisingcode for causing a base station (BS) to receive, from a user equipment(UE), a common uplink (UL) burst in each sub-frame communicated betweenthe UE and the BS, wherein the common UL burst comprises at least one ofa physical layer (PHY) acknowledgement (ACK), a scheduling request (SR),a buffer status report (BSR), or a sounding reference signal (SRS), andcode for causing the BS to receive an UL payload data within at leastone common UL burst of at least one sub-frame communicated between theUE and the BS.

Other aspects, features, and embodiments of the present disclosure willbecome apparent to those of ordinary skill in the art upon reviewing thefollowing description of specific, exemplary embodiments of the presentdisclosure in conjunction with the accompanying figures. While featuresof the present disclosure may be discussed relative to certainembodiments and figures below, all embodiments of the present disclosurecan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the disclosurediscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary wireless communications environmentaccording to embodiments of the present disclosure.

FIG. 2 is a block diagram of an exemplary user equipment (UE) accordingto embodiments of the present disclosure.

FIG. 3 is a block diagram of an exemplary base station according toembodiments of the present disclosure.

FIG. 4 is a diagram of a self-contained Time Division Duplex (TDD)sub-frame according to embodiments of the present disclosure.

FIG. 5 is a diagram illustrating a structure of a common uplink (UL)burst across different sub-frame types according to embodiments of thepresent disclosure.

FIG. 6 is a diagram of an example communication causing mixedinterference among different cells according to embodiments of thepresent disclosure.

FIG. 7 is a diagram illustrating TDD communication among different cellsfor avoiding mixed interference according to embodiments of the presentdisclosure.

FIG. 8 is a flowchart illustrating an exemplary method for wirelesscommunications that may be performed by a user equipment (UE) accordingto embodiments of the present disclosure.

FIG. 9 is a flowchart illustrating an exemplary method for wirelesscommunications that may be performed by a base station (BS) according toembodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to represent the only configurationsin which the concepts described herein may be practiced. The detaileddescription includes specific details for the purpose of providing athorough understanding of the various concepts. However, it will beapparent to those skilled in the art that these concepts may bepracticed without these specific details. In some instances, well-knownstructures and components are shown in block diagram form in order toavoid obscuring such concepts.

The techniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as Evolved UTRA(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part ofUniversal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are new (e.g., 4G networks)releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSMare described in documents from an organization named “3rd GenerationPartnership Project” (3GPP). CDMA2000 and UMB are described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). The techniques described herein may be used for the wirelessnetworks and radio technologies mentioned above as well as otherwireless networks and radio technologies, such as a next generation(e.g., 5^(th) Generation (5G)) network.

FIG. 1 illustrates a wireless communication network 100 in accordancewith various aspects of the present disclosure. The wireless network 100may include a number of base stations 104 and a number of user equipment(UE) 106, all within one or more cells 102 as illustrated in FIG. 1. Forexample, FIG. 1 shows base stations 104 a, 104 b, and 104 c associatedwith cells 102 a, 102 b, and 102 c, respectively. The communicationsenvironment 100 may support operation on multiple carriers (e.g.,waveform signals of different frequencies). Multi-carrier transmitterscan transmit modulated signals simultaneously on the multiple carriers.For example, each modulated signal may be a multi-carrier channelmodulated according to the various radio technologies described above.Each modulated signal may be sent on a different carrier and may carrycontrol information (e.g., pilot signals, control channels, etc.),overhead information, data, etc. The communications environment 100 maybe a multi-carrier LTE network capable of efficiently allocating networkresources. The communications environment 100 is one example of anetwork to which various aspects of the disclosure apply.

A base station (BS) 104 as discussed herein can have variouscharacteristics. In some scenarios, it may include an evolved Node B(eNodeB or eNB) in the LTE context, for example. A base station 104 mayalso be referred to as a base transceiver station or an access point. Itwill be recognized that there could be one to many base stations, aswell as be an assortment of different types such as macro, pico, and/orfemto base stations. The base stations 104 may communicate with eachother and other network elements via one or more backhaul links. Thebase stations 104 communicate with the UEs 106 as shown, including viadirect wireless connections or indirect, e.g., via relay devices. A UE106 may communicate with a base station 104 via an uplink and adownlink. The downlink (or forward link) refers to the communicationlink from a base station 104 to a UE 106. The uplink (or reverse link)refers to the communication link from a UE 106 to a base station 104.

The UEs 106 may be dispersed throughout the wireless network 100, andeach UE 106 may be stationary or mobile. A UE may also be referred to asa terminal, a mobile station, a subscriber unit, etc. A UE 106 may be acellular phone, a smartphone, a personal digital assistant, a wirelessmodem, a laptop computer, a tablet computer, entertainment device,medical device/equipment, biometric devices/equipment, fitness/exercisedevices, vehicular components/sensors, etc. The wireless communicationnetwork 100 is one example of a network to which various aspects of thedisclosure apply.

FIG. 2 is a block diagram of UE 106 according to embodiments of thepresent disclosure. The UE 106 may include a processor 202, a memory204, a transmission access resource selection module 208, a transceiver210, and an antenna 216. These elements may be in direct or indirectcommunication with each other, for example via one or more buses.

The processor 202 may include a central processing unit (CPU), a digitalsignal processor (DSP), an application-specific integrated circuit(ASIC), a controller, a field programmable gate array (FPGA) device,another hardware device, a firmware device, or any combination thereofconfigured to perform the operations described herein. The processor 202may also be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The memory 204 may include a cache memory (e.g., a cache memory of theprocessor 442), random access memory (RAM), magnetoresistive RAM (MRAM),read-only memory (ROM), programmable read-only memory (PROM), erasableprogrammable read only memory (EPROM), electrically erasableprogrammable read only memory (EEPROM), flash memory, solid state memorydevice, hard disk drives, other forms of volatile and non-volatilememory, or a combination of different types of memory. In an embodiment,the memory 204 includes a non-transitory computer-readable medium. Thememory 204 may store instructions 206. The instructions 206 may includeinstructions that, when executed by the processor 202, cause theprocessor 202 to perform the operations described herein with referenceto the UE 106 in connection with embodiments of the present disclosure.Instructions 206 may also be referred to as code. The terms“instructions” and “code” may include any type of computer-readablestatement(s). For example, the terms “instructions” and “code” may referto one or more programs, routines, sub-routines, functions, procedures,etc. “Instructions” and “code” may include a single computer-readablestatement or many computer-readable statements. The transmission accessresource selection module 208 may be configured to select and assignresources (e.g., time resources and/or frequency resources) fortransmission of uplink bursts from UE 106, discussed in more detailbelow.

The transceiver 210 may include a modem subsystem 212 and a radiofrequency (RF) unit 214. The transceiver 210 is configured tocommunicate bi-directionally with other devices, such as base stations104. The modem subsystem 212 may be configured to modulate and/or encodethe data from the memory 204 and/or the transmission access resourceselection module 208 (and/or from another source, such as some type ofsensor) according to a modulation and coding scheme (MCS), e.g., alow-density parity check (LDPC) coding scheme, a turbo coding scheme, aconvolutional coding scheme, etc. The RF unit 214 may be configured toprocess (e.g., perform analog to digital conversion or digital to analogconversion, etc.) modulated/encoded data from the modem subsystem 212(on outbound transmissions) or of transmissions originating from anothersource such as a base station 104. Although shown as integrated togetherin transceiver 210, the modem subsystem 212 and the RF unit 214 may beseparate devices that are coupled together at the UE 106 to enable theUE 106 to communicate with other devices.

The RF unit 214 may provide the modulated and/or processed data, e.g.data packets (or, more generally, data messages which may contain one ormore data packets and other information), to the antenna 216 fortransmission to one or more other devices. This may include, forexample, transmission of data to a base station 104 according toembodiments of the present disclosure. The antenna 216 may furtherreceive data messages transmitted from a base station 104 and providethe received data messages for processing and/or demodulation at thetransceiver 210. Although FIG. 2 illustrates antenna 216 as a singleantenna, antenna 216 may include multiple antennas of similar ordifferent designs in order to sustain multiple transmission links.

FIG. 3 is a block diagram of an exemplary base station 104 according toembodiments of the present disclosure. The base station 104 may includea processor 302, a memory 304, a resource coordination module 308, atransceiver 310, and an antenna 316. These elements may be in direct orindirect communication with each other, for example via one or morebuses. The base station 104 may be an evolved Node B (eNodeB or eNB), amacro cell, a pico cell, a femto cell, a relay station, an access point,or another electronic device operable to perform the operationsdescribed herein with respect to the base station 104. The base station104 may operate in accordance with one or more communication standards,such as a 3rd generation (3G) wireless communication standard, a 4thgeneration (4G) wireless communication standard, a long term evolution(LTE) wireless communication standard, an LTE-advanced wirelesscommunication standard, or another wireless communication standard nowknown or later developed (e.g., a next generation network operatingaccording to a 5G protocol).

The processor 302 may include a CPU, a DSP, an ASIC, a controller, aFPGA device, another hardware device, a firmware device, or anycombination thereof configured to perform the operations describedherein with reference to the base station 104 introduced in FIG. 1above. The processor 302 may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The memory 304 may include a cache memory (e.g., a cache memory of theprocessor 302), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, asolid state memory device, one or more hard disk drives, other forms ofvolatile and non-volatile memory, or a combination of different types ofmemory. In an embodiment, the memory 304 includes a non-transitorycomputer-readable medium. The memory 304 may store instructions 306. Theinstructions 306 may include instructions that, when executed by theprocessor 302, cause the processor 302 to perform the operationsdescribed herein with reference to the base station 104 in connectionwith embodiments of the present disclosure. Instructions 306 may also bereferred to as code, which may be interpreted broadly to include anytype of computer-readable statement(s) as discussed above with respectto FIG. 2. The resource coordination module 308 may be configured tocoordinate resource usage (e.g., time resources and/or frequencyresources) among the base stations 104 when communicating with the UEs106, such as to mitigate or at least reduce interference among the basestations 104.

The transceiver 310 may include a modem subsystem 312 and a radiofrequency (RF) unit 314. The transceiver 310 is configured tocommunicate bi-directionally with other devices, such as UEs 106. Themodem subsystem 312 may be configured to modulate and/or encode dataaccording to a MCS, some examples of which have been listed above withrespect to FIG. 2. The RF unit 314 may be configured to process (e.g.,perform analog to digital conversion or digital to analog conversion,etc.) of modulated/encoded data from the modem subsystem 312 (onoutbound transmissions) or of transmissions originating from anothersource, such as an UE 106. Although shown as integrated together intransceiver 310, the modem subsystem 312 and the RF unit 314 may beseparate devices that are coupled together at the base station 104 toenable the base station 104 to communicate with other devices.

The RF unit 314 may provide the modulated and/or processed data, e.g.data packets, to the antenna 316 for transmission to one or more otherdevices such as UEs 106. The modem subsystem 312 may modulate and/orencode the data in preparation for transmission. The RF unit 314 mayreceive the modulated and/or encoded data packet and process the datapacket prior to passing it on to the antenna 316. This may include, forexample, transmission of data messages to UEs 106 or to another basestation 104, according to embodiments of the present disclosure. Theantenna 316 may further receive data messages transmitted from UEs 106,and provide the received data messages for processing and/ordemodulation at the transceiver 310. Although FIG. 3 illustrates antenna316 as a single antenna, antenna 316 may include multiple antennas ofsimilar or different designs in order to sustain multiple transmissionlinks.

FIG. 4 is a self-contained Time Division Duplex (TDD) sub-framestructure 400 with a common uplink burst design according to embodimentsof the present disclosure. As illustrated in FIG. 4, the TDD sub-framestructure 400 may comprise a plurality of downlink (DL) centricsub-frames 402 and at least one uplink (UL) centric sub-frame 404 foreach communication cycle 406 between eNB (e.g., eNB 104) and UE (e.g.,UE 106). Each DL centric sub-frame 402 may comprise a Physical DownlinkShared Channel (PDSCH) 408 (long DL burst), and a common UL burst 410(short UL burst). Each UL centric sub-frame 404 may comprise a short DLburst 412 and a long UL burst 414. In general, due to asymmetry betweenDL traffic and UL traffic, a number of DL centric sub-frames 402 percommunication cycle 406 can be greater than a number of UL centricsub-frames 404. The ratio can be fixed or variable. In some instances,the number of UL centric sub-frames 404 is greater than the number of DLcentric sub-frames 402. For some embodiments, each DL centric sub-frame402 and UL centric sub-frame 404 of the TDD sub-frame structure 400 maybe communicated during a transmission time interval (TTI) with durationof 0.25 ms (e.g., short sub-frame structure). In this case, each commonUL burst structure (e.g., the common UL burst 412, and the common ULburst 418) may comprise, for example, two short orthogonal frequencydivision multiplexing (OFDM) symbols having duration of approximately 33μs (e.g., for sub-carrier spacing of 60 kHz). It is understood that theframe structure and associated lengths of time of TTIs, PDSCHs, DLbursts, UL bursts, and/or common UL bursts may vary.

Embodiments of the present disclosure relate to decoupling uplinkcontrol latency from the UL/DL switching pattern using common UL burst.There may be several UL channels with time critical information. Forsome embodiments, a Physical layer (PHY) Acknowledgement (ACK) or aNegative Acknowledgement (NACK) in DL centric sub-frames 402 may be timecritical information. The ACK/NACK may be transmitted to acknowledge (ornegatively acknowledge) DL data sent on PDSCH. The objective may be totransmit ACK/NACK within the same sub-frame as the PDSCH (achievingself-contained) in to reduce Hybrid Automatic Repeat Request (HARQ)delay.

For some embodiments, a Scheduling Request (SR) bit may be time criticalinformation. The SR bit may indicate a request for the eNB to provide ULgrant so that the UE can transmit Physical Uplink Shared Channel(PUSCH). The objective may be to transmit SR from the UE to the eNB ineither DL centric sub-frame 402 or in UL centric sub-frame 404 in orderto avoid extra latency in waiting for UL centric sub-frame 404. In oneor more embodiments, SR may also include information about Buffer StatusReport (BSR) at the UE. The BSR may provide a serving eNB withinformation about an amount of data available for transmission in ULbuffers of the UE.

For some embodiments, a Sounding Reference Signal (SRS) may be timecritical information. The SRS transmitted from the UE to the eNB mayallow the eNB to quickly sound a channel between the eNB and the UEwhenever there is a DL traffic. The SRS received at the eNB may alsoallow the eNB to closely track the channel fading. Preferably, the SRSmay be received by the eNB immediately before the DL burst istransmitted from the eNB to the UE. As discussed, these time criticalinformation (e.g., at least one of ACK, NACK, SR, BSR, or SRS) should betransmitted regardless of UL-centric or DL-centric sub-frames.

FIG. 5 is a diagram 500 illustrating common UL burst across differentsub-frame types according to embodiments of the present disclosure. Asillustrated in FIG. 5, each DL centric sub-frame 502 may comprise aPhysical Downlink Control Channel (PDCCH) 504, a Physical DownlinkShared Channel (PDSCH) 506, and a common UL burst 508. Each UL centricsub-frame 510 may comprise a PDCCH 512, a regular UL burst 514, and acommon UL burst 516. It can be observed that the same common UL burststructure may be present in both the DL centric sub-frames and the ULcentric sub-frames, e.g., the common UL bursts 508 and 516 may comprisethe same structure incorporated into each DL centric sub-frame 502 andeach UL centric sub-frame 510.

As illustrated in FIG. 5, the common UL burst may be present in allsub-frames. DL-centric sub-frames may comprise (beside DL channels) onlythe common UL burst (e.g., the common UL burst 508), whereas UL-centricsub-frames may comprise both the regular UL burst (e.g., regular ULburst 514 in FIG. 5) and the common UL burst (e.g., the common UL burst516). In an embodiment of the present disclosure, the common UL burst inall sub-frames may occupy the same frequency/time resources within thenetwork.

In accordance with embodiments of the present disclosure, time criticalUL control information may be transmitted in a common UL burst of eitherDL centric sub-frame (e.g., in common UL burst 508) or UL centricsub-frame (e.g., in common UL burst 516). For some embodiments, asdiscussed, time critical UL control information may comprise at leastone of PHY ACK/NACK, SR, BSR, or SRS.

For some embodiments, a UE can opportunistically send Physical UplinkShared Channel (PUSCH) data depending on available uplink headroom. Thismay be applicable to small cell or macro cell center users. Inaccordance with embodiments of the present disclosure, a common UL burst(e.g., in either DL centric sub-frame or UL centric sub-frame) may beused, by a UE, to transmit scheduled uplink payload data (e.g., PUSCH)in order to achieve low latency. Therefore, low latency uplink data maybe communicated between the UE and the eNB using the common UL burst.

Certain applications have requirements on a tolerable delay for uplinkdata. For example, in order to support high Transmission ControlProtocol (TCP) throughput in downlink, application layer ACK may need tobe transmitted within a short time window. Users with enough powerheadroom may utilize a common UL burst to transmit the low latencyuplink data. This may be applicable to small cells or cell users inlarge cells. For some embodiments, those UEs that want to use commonuplink burst to transmit payload data need to transmit an appropriaterequest to the eNB. Then, the eNB may schedule, based upon the receivedrequest, transmission of UL payload data in common UL bursts based onthe UE's power headroom and resource availability.

For certain embodiments of the present disclosure, common UL bursts maybe utilized to achieve communications free of mixed interference, or atleast with reduced mixed interference. FIG. 6 is a diagram 600 of anexample communication causing mixed interference among different cellsaccording to embodiments of the present disclosure. For someembodiments, the eNB can potentially change communication of somescheduled DL-centric sub-frames into UL-centric sub-frames (and viceversa) within a cell, depending on traffic needs. This dynamic DL-ULswitching may cause mixed interference among different cells. Forexample, as illustrated in FIG. 6, DL transmission 602 of base station604 may interfere with UL communication 608 received at base station 610(e.g., DL-to-UL interference 614 occurring at base station 604 and basestation 610 of different cells). In the same time, UL transmission 608from UE 612 may interfere with DL communication 602 at UE 606 (e.g.,UL-to-DL interference 616 occurring at UE 606 and UE 612 of differentcells). In accordance with embodiments of the present disclosure, commonuplink design may allow the uplink control information to becommunicated without causing mixed interference during dynamic UL-DLswitching.

FIG. 7 is a structure 700 illustrating TDD communication among differentcells for avoiding mixed interference according to embodiments of thepresent disclosure. As illustrated in FIG. 7, in Cell 2, UL-to-DLswitching may occur (e.g., due to certain traffic needs), and there maybe simultaneous communication of UL centric sub-frame 702 in Cell 1 andDL centric sub-frame 704 in Cell 2. The UL centric sub-frame 702 maycomprise PDCCH 706, regular UL burst 708, and common UL burst 710,whereas DL centric sub-frame 704 may comprise PDCCH 712, DL burst 714,and common UL burst 716, as illustrated in FIG. 7. It can be observedthat there is no mixed interference between PDCCH 706 and PDCCH 712since each PDCCH can be decoded based on a unique spreading sequence(e.g., PDCCH 706 and PDCCH 712 can be orthogonal to each other).Similarly, there is no mixed interference between common UL burst 710and common UL burst 716 since each common UL burst can be spread with aunique spreading sequence (e.g., common UL burst 710 and common UL burst716 can be orthogonal to each other).

FIG. 8 is a flowchart illustrating an exemplary method 800 for accordingto embodiments of the present disclosure. The method 800 may beimplemented in UE 106. The method 800 will be described with respect toa single UE 106 for simplicity of discussion, though it will berecognized that the aspects described herein may be applicable to aplurality of UEs 106, including a network of UEs. It is understood thatadditional method blocks can be provided before, during, and after theblocks of method 800, and that some of the blocks described can bereplaced or eliminated for other embodiments of the method 800.

At block 802, UE may transmit, to a base station, a common UL burst(e.g., common UL burst 508 from FIG. 5, common UL burst 516 from FIG. 5)in each sub-frame (e.g., DL centric sub-frame 502 from FIG. 5, ULcentric sub-frame 510 from FIG. 5) communicated between the UE and thebase station, wherein the common UL burst comprises at least one of PHYACK, SR, BSR, or SRS. At block 804, the UE may transmit scheduled ULpayload data in at least one common UL burst (e.g., at least one ofcommon UL burst 508 or common UL burst 516 from FIG. 5) of at least onesub-frame (e.g., at least one of DL centric sub-frame 502 or UL centricsub-frame 510 from FIG. 5) communicated between the UE and the basestation.

FIG. 9 is a flowchart illustrating an exemplary method 900 for accordingto embodiments of the present disclosure. The method 900 may beimplemented in the base station 104. The method 900 will be describedwith respect to a single base station 104 in communication with a singleUE 106 for simplicity of discussion, though it will be recognized thatthe aspects described herein may be applicable to a plurality of UEs 106and/or base stations 104. It is understood that additional method blockscan be provided before, during, and after the blocks of method 900, andthat some of the blocks described can be replaced or eliminated forother embodiments of the method 900.

At block 902, a base station may receive, from UE, a common UL burst(e.g., common UL burst 508 from FIG. 5, common UL burst 516 from FIG. 5)in each sub-frame (e.g., DL centric sub-frame 502 from FIG. 5, ULcentric sub-frame 510 from FIG. 5) communicated between the UE and thebase station, wherein the common UL burst comprises at least one of PHYACK, SR, BSR, or SRS. At block 904, the base station may receive an ULpayload data within at least one common UL burst (e.g., at least one ofcommon UL burst 508 or common UL burst 516 from FIG. 5) of at least onesub-frame (e.g., at least one of DL centric sub-frame 502 or UL centricsub-frame 510 from FIG. 5) communicated between the UE and the basestation.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Also, as used herein, including in the claims, “or” as used in a list ofitems (for example, a list of items prefaced by a phrase such as “atleast one of” or “one or more of”) indicates an inclusive list suchthat, for example, a list of [at least one of A, B, or C] means A or Bor C or AB or AC or BC or ABC (i.e., A and B and C). It is alsocontemplated that the features, components, actions, and/or stepsdescribed with respect to one embodiment may be structured in differentorder than as presented herein and/or combined with the features,components, actions, and/or steps described with respect to otherembodiments of the present disclosure.

As those of some skill in this art will by now appreciate and dependingon the particular application at hand, many modifications, substitutionsand variations can be made in and to the materials, apparatus,configurations and methods of use of the devices of the presentdisclosure without departing from the spirit and scope thereof. In lightof this, the scope of the present disclosure should not be limited tothat of the particular embodiments illustrated and described herein, asthey are merely by way of some examples thereof, but rather, should befully commensurate with that of the claims appended hereafter and theirfunctional equivalents.

What is claimed is:
 1. A method for wireless communications, comprising:receiving, at a base station (BS) from a user equipment (UE), a commonuplink (UL) burst in each sub-frame communicated between the UE and theBS, wherein the common UL burst comprises at least one of a physicallayer (PHY) acknowledgement (ACK), a scheduling request (SR), a bufferstatus report (BSR), or a sounding reference signal (SRS); receiving, atthe BS, an UL payload data within at least one common UL burst of atleast one sub-frame communicated between the UE and the BS; andswitching, by the BS based on a traffic, communication of a scheduled ULcentric sub-frame to communication of a downlink (DL) centric sub-framehaving a Physical Downlink Control Channel (PDCCH) and the common ULburst.